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cold start problem
My friend has a 2.7, 1977 S.
It is a pig on first start up - too lean. Once you actually get it firing, the warm up is fine. But lots of backfire, misfire at the cranking stage.
We have done all the obvious stuff, I think. The CSV is working, as is the thermo switch (but I still suspect something wrong here). The only thing we have not done is pull the CSV out and actually watch fuel go thru it - but I dont think they have a screen, and you can hear and feel it click on/off.
The WUR cold pressure is 16 psi - which must be about as low as they go for cold WUR numbers. And the warm up phase is fine. The thermo switch which controls vac enrich/lean to the WUR is working and cuts in after about 30 sec.
The dizzy vac adv is working.
As far as we can find, no airleaks, and the car runs fine at all phases other than cold crank.
The accumulator is holding pressure as per the book.
Apparently? the 911S around this era had a cold start issue?
Not sure where else to look now. One possibility would be to try and extend the thermoswitch duration to full crank time?
If you prime the injectors at dead cold, it starts and idles first off.
Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
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